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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.gemstone.gemfire.cache.lucene.internal;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import org.apache.logging.log4j.Logger;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.queryparser.classic.MultiFieldQueryParser;
import org.apache.lucene.queryparser.classic.ParseException;
import org.apache.lucene.search.Query;

import com.gemstone.gemfire.DataSerializer;
import com.gemstone.gemfire.cache.lucene.LuceneIndex;
import com.gemstone.gemfire.cache.lucene.LuceneQueryProvider;
import com.gemstone.gemfire.cache.query.QueryException;
import com.gemstone.gemfire.internal.DataSerializableFixedID;
import com.gemstone.gemfire.internal.Version;
import com.gemstone.gemfire.internal.logging.LogService;

/**
 * Constructs a Lucene Query object by parsing a search string. The class uses {@link MultiFieldQueryParser}. It sets
 * searchable fields in a {@link LuceneIndex} as default fields.
 */
public class StringQueryProvider implements LuceneQueryProvider, DataSerializableFixedID {
  private static final long serialVersionUID = 1L;

  private static final Logger logger = LogService.getLogger();

  // the following members hold input data and needs to be sent on wire
  private String query;

  // the following members hold derived objects and need not be serialized
  private transient Query luceneQuery;

  public StringQueryProvider() {
    this(null);
  }

  public StringQueryProvider(String query) {
    this.query = query;
  }

  @Override
  public synchronized Query getQuery(LuceneIndex index) throws QueryException {
    if (luceneQuery == null) {
      String[] fields = index.getFieldNames();

      //TODO  get the analyzer from the index
      MultiFieldQueryParser parser = new MultiFieldQueryParser(fields, new StandardAnalyzer());
      try {
        luceneQuery = parser.parse(query);
      } catch (ParseException e) {
        logger.debug("Malformed lucene query: " + query, e);
        throw new QueryException(e);
      }
    }
    return luceneQuery;
  }

  /**
   * @return the query string used to construct this query provider
   */
  public String getQueryString() {
    return query;
  }

  @Override
  public Version[] getSerializationVersions() {
    return null;
  }

  @Override
  public int getDSFID() {
    return LUCENE_STRING_QUERY_PROVIDER;
  }

  @Override
  public void toData(DataOutput out) throws IOException {
    DataSerializer.writeString(query, out);
  }

  @Override
  public void fromData(DataInput in) throws IOException, ClassNotFoundException {
    query = DataSerializer.readString(in);
  }
}